Friday, 16 May 2014

Periaeschna nocturnalis - not magdalena afterall

*After communication with Wen Chi-Yeh, I went back to the description and drawings in Asahina of P. nocturnalis. There are several indications that point to that species. No clear basal patches in the wings, the straight line on the metepimeron, the reddish brown legs, the shape of the cerci and the abdominal pattern. For now I will consider these individuals as this taxon (updated June 16, 2014).

Two weeks ago I failed to catch a Periaeschna species in Yen Bai Province, although I did take some pictures and from that it appears to be P. magdalena. See the concerned entry. Luckily, when working the streams around Nam Bung on May 11, I bumped into several Aeshnids and was able to catch one and take pictures of a female. In hand there seemed little doubt that at these were P. magdalena, although they appear more yellow and less green than the specimen a week earlier and had differently colored eyes. However, by now (mid-June) I have caught several other P. magdalena, in Ba Vi and Xuan Son. They invariably display all dark legs, dark blue eyes, much darker thorax pattern contrasting with the light stripes, differently shaped antehumerals and differently shaped appendages. In fact, they are very different insects. I handed over my male specimen of this species to Karube, so I cannot check it now, but this must be a different Periaeschna species.

Male Periaeschna sp., a quite beautiful Aeshnid

Thorax and head in close-up

The female hanging in a bush at a safe distance


The appendages, close to Asahina (1981), but in fact slightly different

And likewise, in lateral view

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